#container {
    width:600px;
    height:600px;
    outline:1px solid;
}

.jtk-node {
    outline:1px solid;
    padding:3px;
    display:flex;
    align-items:center;
    justify-content:center;
}

.hello-node {
    width:100px;
    height:80px;
    background-color:white;
}

.world-node {
    width:80px;
    height:80px;
    border-radius:50%;
    background-color:purple;
    color:white;
    font-weight:bold;
}
